BACKGROUND Biomass growth of Pencillium chrysogenum is characterised by a distinct pellet morphology consisting of compact hyphal agglomerates. Fungal pellets are advantageous in industrial process control due to rheological advantages but lead to biomass degradation due to diffusional limitations of oxygen and substrate in the pellet's core. Several fermentation parameters are known to affect key pellet characteristics regarding morphology, viability and productivity. Pellet morphology and size are affected by agitation. Biomass viability and productivity are tightly interlinked with substrate uptake and dissolved oxygen concentration. RESULTS The goal of this study was to study the impact of the fermentation parameters power input, dissolved oxygen content and specific substrate uptake rate on morphology, biomass viability and productivity. A design of experiments (DoE) approach was conducted and corresponding responses were analysed using novel morphological descriptors analysed by a previously established flow cytometry method. Results clearly display inverse correlations between power input and pellet size, specific morphological parameters related to pellet density can be increased in direct proportion to power input. Biomass viability and productivity are negatively affected by high specific substrate uptake rates. CONCLUSIONS Based upon multiple linear regression, it was possible to obtain an optimal design space for enhanced viability and productivity at beneficial morphological conditions. We could maintain a high number of pellets with favourable morphology at a power input of 1500 W/m3. A sound compromise between viability and high productivity is possible at a specific glucose uptake rate of 0.043 g/g/h at dissolved oxygen levels of 40% minimum.

中文翻译：

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最佳的工艺设计空间，可通过形态和生理控制，确保分批补料培养过程中产黄青霉丸的最大活力和生产力。

背景技术产黄青霉的生物质生长的特征在于由紧密的菌丝附聚物组成的独特的颗粒形态。真菌颗粒由于具有流变学优势而在工业过程控制中具有优势，但由于氧气和底物在颗粒芯中的扩散限制而导致生物质降解。已知有几种发酵参数会影响关键粒料的形态，活力和生产率。球粒的形态和大小受搅拌的影响。生物量的生存能力和生产力与底物吸收和溶解氧浓度紧密相关。结果本研究的目的是研究发酵参数功率输入，溶解氧含量和特定底物摄取速率对形态，生物量活力和生产力的影响。进行了实验设计（DoE）方法，并使用通过先前建立的流式细胞术方法分析的新型形态学描述符分析了相应的响应。结果清楚地显示出功率输入与颗粒尺寸之间的反相关关系，与颗粒密度相关的特定形态参数可以与功率输入成正比地增加。生物量的生存能力和生产率受到高的特定底物摄取率的不利影响。结论基于多元线性回归，有可能获得最佳设计空间，以在有利的形态学条件下提高生存能力和生产率。我们可以在1500 W / m3的功率输入下保持大量具有良好形态的颗粒。